The invention relates to an expandable shaft for releasably engaging a tubular core about which a web is wound, for example cloth wound on a cloth winding machine. In particular, the invention relates to improved operators for actuating an expandable shaft.
Prior expandable shafts are known, for example, in related U.S. Pat. Nos. 4,492,346 and 4,469,288, which use operator rods moving axially to cause core engagers to move radially to lock within and against the core. A drive screw threaded in a journal abuts the operator rod to move it axially to engage the core engagers. The rod is returned under spring pressure. An arrangement of pressure washers are used to dampen vibrations and prevent the drive screw from loosening and retracting in use. Other operator devices for expandable shafts and mandrels are disclosed in U.S. Pat. Nos. 3,722,808, 3,331,565, 2,670,905, and 2,394,503. U.S. Pat. No. 2,394,503 uses air to move an operator rod for expanding members to engage a core. U.S. Pat. No. 3,331,565 and 2,670,905 use manual buttons to operate an expandable shaft. U.S. Pat. No. 3,722,808 discloses a rather complex air operator for an expandable shaft which uses a compression spring to retain the shaft expanded and air pressure to release the shaft. The mechanical operators of the prior art have lacked simple reliable operators having a positive locking of a shaft in its expanded position. The actuator mechanisms acted upon by the operators to expand the shaft or mandrels have tended to be too complex for the rather simple application being made.
Accordingly, an object of the invention is to provide a simple and reliable operator for an expandable shaft which may be positively locked to prevent the operator from loosening during operation.
Another object of the invention is to provide an expansion unit for actuating an expandable shaft which is simple in construction and operation and may be duplicated along the length of the shaft to provide as many units as needed for the particular application being made.
Another object of the invention is to provide improved manual and automatic operators for an expandable shaft having expansion units which more simply and reliably expand the shaft in response to the operator.
Still another object of the invention is to provide automatic and manual fluid operators for use with expansion units for expanding a shaft on a winding stand and the like.